1. Field of the Invention
The present invention relates to a vaporizer for generating a process gas from a gas-liquid mixture fluid, a gas generating apparatus for generating a process gas from a liquid material, and a semiconductor processing system. The term “semiconductor process” used herein includes various kinds of processes which are performed to manufacture a semiconductor device or a structure having wiring layers, electrodes, and the like to be connected to a semiconductor device, on a target substrate, such as a semiconductor wafer or a glass substrate used for an LCD (Liquid Crystal Display) or FPD (Flat Panel Display), by forming semiconductor layers, insulating layers, and conductive layers in predetermined patterns on the target substrate.
2. Description of the Related Art
A film formation process for forming a predetermined film on the surface of a semiconductor wafer is performed in manufacturing semiconductor devices. For example, a process of this kind is performed, using a low-pressure CVD (Chemical Vapor Deposition) apparatus. In low-pressure CVD apparatuses, a source material is supplied in a gaseous state to promote a chemical reaction, thereby depositing a thin film on the surface of a wafer. In apparatuses of this kind, there is a case where a process gas is generated by vaporizing a liquid material, and is supplied into a process chamber as a film formation gas.
Examples of a film formation process using a process gas generated by vaporizing a liquid material are as follows. Specifically, a process gas generated by vaporizing TEOS (tetraethoxysilane), and oxygen (O2) gas are used to form an SiO2 film. A process gas generated by vaporizing Si2Cl6, and ammonia (NH3) gas are used to form a silicon nitride (Si3N4) film.
There is known a baking type and a VC (Vapor Control) type as systems for vaporizing a liquid material. The baking type is configured to supply a liquid material into a heating vessel and vaporize it by heating. The VC type is a simplification of the baking type, and is configured to vaporize a liquid material by bringing it into direct contact with a vaporizing portion. The baking type is suitable for vaporization of TEOS, which has a vapor pressure of 5.6 kPa (42 Torr) at about 85° C., and HCD (Si2Cl6), which has a vapor pressure of 14.4 kPa (108 Torr) at about 85° C. The VC type is suitable for vaporization of TEOS, and BTBAS (SiH2[NH(C4H9)]2), which has a vapor pressure of 6.7 kPa (50 Torr) at about 85° C.